Dobby for looms



Oct. 1, 1968 P. SAMSON 3,

DOBBY FOR LOOMS Filed July 29, 1966 5 Sheets-Sheet 1 P. SAMSON DOBBY FOR LOOMS Oct. 1, 1968 5 Sheets-Sheet 2 Filed July 29, 1966 Oct. 1, 1968 P. SAMSON 3,

DOBBY FOR LOOMS Filed July 29, 1966 5' Sheets-Sheet 4 0a. 1, 1968 P. SAMSON 3,403,705

DOBBY FOR LOOMS Filed July 29, 1966 5 Sheets-Sheet 5 Pics/I1 United States Patent 9 Claims. (Cl. 139-68) ABSTRACT OF THE DISCLOSURE A dobby having two hooks pivotally secured to each end of a balance the middle point of which is operatively connected with a heald frame and two knives operating in alternation once for every two picks, the ends of the said balance being engaged by abutments. Each abutment is supported on a plate pivotably connected to the center of the balance and the abutments are shifted by the plate in alternation away from and back towards the corresponding end of the balancesimultaneously with the forward movement of the associated knife, the rearward movement of each abutment causing movement of the corresponding hook into the path of the cooperating knife to make said hook accompany the knife prior to engagement therewith.

The present invention relates to dobbies for looms. Such dobbies allow the loom shafts to remain in their raised or lowered position for several successive picks without returning each time into their central position or into their lower shed position.

Such dobbies are well known and operate for successive alternating sheds; in other words, they include two sets of wires and two blades operating in alternation once for every two picks, that is once for every two revolutions of the loom.

Each of the levers producing a tractional action on the heald frames is secured to the middle of a member termed the balance. The latter may be actuated in alternation by two hooks secured respectively to the two ends of the balance.

The balance may thus operate under tractional conditions if the nose of a hook is engaged by the blade which is progressing. In contradistinction, the balance is in its lower position when the nose of the hook is not engaged by the blade. In order to produce a predetermined weave, it is necessary to control the hooks by means of a suitable mechanism controlled by small boards provided with keys or perforations or perforated paper. Such control of the hooks should be performed accurately at the moment at which they are released by the blades. To this end, the blade executes a receding movement which is larger than that of the hook which is held fast by a stationary abutment. The distance between the nose of the hook and the edge of the blade when the blade is in its rearmost position is termed the release spacing. Said spacing varies with the design of the dobby. In older dobbies said spacing is as high as 7 mm. It has been sometimes reduced but if it is desired to obtain dobbies operating at high speeds, said spacing should be a minimum. As a matter of fact, when the blade engages the hook so as to draw it forwardly, it subjects the hook to a shock whose intensity is greater with increased spacing. This shock results in a vibrationof the heald frame and consequently of the warp threads on the loom.

Heretofore known improvements in reducing the spacing have the drawback of limiting the speed of operation. The present invention has for an object to provide a novel dobby which eliminates the aforesaid drawback. To this end, the invention contemplates the provision of a dobby 3,403,705 Patented Oct. 1, 1968 "ice for a weaving loom of the type referred to wherein the abutments provided for the balance are shifted reciprocatingly rearwardly and forwardly at the end of each stroke of the blades in a manner such that the hooks carried by the balance accompanying the blades at the moment corresponding to their engagement.

Said movement of the blades accompanied by the hooks at the moment of the engagement not only damps the shocks and vibrations due to the contact between the blades and the hooks, but it allows furthermore reducing considerably the spacing referred to in a fully reliable manner since a "sufiicient time is available for the execution of the selection. Such a dobby thus allows operating at high speeds.

According to an embodiment of this improved dobby, the abutments of the balance are carried by a plate adapted to pivot around an axis passing through the middle of the balance. Said plate is adapted to pivot in opposite directions, at the ends of the strokes of the blades through the agency of a lever engaging a heart-shaped cam keyed to the same shaft as that which controls the movement of the blades and executes one half revolution for each revolution of the loom.

According to a preferred embodiment of such a dobby, the plate carrying the abutments for the balance also carries two levers which are normally urged by springs into contacting relationship with the rear surfaces of the abutmerits of the balance, each lever being provided with a boss against which further springs urge the tail-end of the of the hooks of the balance. Said levers are held, when required, in a rear position by a bolt controlled by a reading system, such that during the forward stroke of a corresponding abutment, the tail end of the hook is released and a notch therein is brought by one of the last mentioned springs into the path of the blade.

According to an advantageous embodiment of said dobby, the blades are carried by the ends of the arms of two T-shaped levers of which the central arm, revolvably secured to a stationary pivot, is driven into an oscillatory movement, by a connecting rod controlled in its turn by an eccentric member keyed to a shaft executing one half revolution for each revolution of the loom.

The reading system associated with said dobby and controlling said bolts may be of any known type. However, according to a further feature of the invention said reading system is connected with the dobby through adaptable mechanical or electric means.

This solution has the advantage of allowing a reading of the design with an arrangement whose pitch differs from that of the dobby.

In the case of a reading performed by means of a board and keys, the ends of the associated plates are connected through cables with the corresponding lever-holding bolts which are normally held in a retracted position by further springs.

According to a still further embodiment of said reading system, each of a switch its plates controls such that when a key raises said plate the switch is closed thereby closing a circuit incorporating an electro-magnet which controls in its turn the operation of the corresponding bolt.

If the dobby is to be used for only one direction of operation, the switches can be controlled directly by the keys.

In the case of a reading of the design by a perforated strip of paper progressing over two metal plates under two rows of yielding metal blades forming, for instance, a corresponding member of switches as there are blades, each switch controls an electro-magnet associated with a predetermined bolt.

The invention will be readily understood from a reading of the following description, reference being made to the accompanying diagrammatic drawings illustrating by way of example and by no means in a limiting sense, a number of embodiments of the improved dobby and of its control system executed in accordance with the invention. In said drawings:

FIG. 1 is an elevational view of the weaving mechanism including a dobby.

FIG. 2 illustrates partly in section and on a larger scale, the improved portion of the dobby in accordance with the invention.

FIG. 3 shows a plate carrying the abutments of the balance and the control means for said plate.

FIG. 4 illustrates a blade-carrying lever and its driving means.

FIG. 5 is a sectional view through line 55 of FIG. 3.

FIG. 6 is a sectional view through line 6-6 of FIG. 4.

FIG. 7 illustrates an embodiment of a mechanical connection between the design-reading system and the dobby in the case of a reading through keys.

FIG. 8 illustrates an electric connection as a substitute for the connection illustrated in FIG. 7.

FIGS. 9 and 10 illustrate, respectively in elevational and in plan view as seen from above, a conventional design reading system operating by means of a perforated paper strip as employed by the present invention.

FIG. 11 illustrates an embodiment of an electric circuit connecting the reading system according to FIGS. 9 and 10 with the dobby according to the invention.

In FIG. 1 is shown a weaving mechanism inclusive of a dobby, of which only the lever 10 is shown in detail. The lever 10 is coupled with the heald frames 2 in a conventional manner, that is through the agency of the rods 3, the notched levers 4, the connecting rods 5, and suspension levers 6, the whole arrangement being carried by the frame 7.

The improved dobby is illustrated with further detail in FIGS. 2 to 6.

A balance 11 is coupled to a tractionally acting lever 10 at its middle point 12 through the agency of a rigid link system 13. Said balance carries pivotally at its ends the hooks 14 and 15 which are urged normally into their operative positions by springs 16 and 17. Each hook 14, 15 has a nose respectively shown at 14a and 15a for engagement with the corresponding blade illustrated respectively at 18 and at 19. Each hook 14 and 15 includes furthermore a tail piece illustrated respectively at 14b and 15b which tail-piece under the action of the corresponding spring 16 or 17 is urged against a boss provided on a respective selecting lever 21 or 22. At each end of its rear surface, the balance 11 is provided with a roller respectively illustrated at 23 and at 24, said rollers engaging each a corresponding abutment 25 or 26.

As shown by their positions illustrated in dot-anddash lines and in contradistinction with the conventional dobbies, the abutments 25 and 26 undergo during each complete stroke of the batten displacement parallel with that of the corresponding blade 18, 19. Thus, when the blade 18 reaches the end of its rearward travel in the direction of the arrow 27, abutment 25 is shifted in the same direction into the position illustrated in dot-anddash lines. At the same time, the abutment 26 is shifted forwardly by an equal distance. The abutments 25, 26 undergo equal angular movement the center of which registers with the middle point 12 of the balance 11, so that said movement of the abutments 25 and 26 has no action on the lever 10 which pivots thereby around the point 12 of the balance.

When the blade 19 reaches in its turn the end of its rearward travel, the abutments 25 and 26 are shifted in the opposite directions.

FIG. 3 illustrates an embodiment of the means driving the abutments 25 and 26 in an oscillatory movement. In said FIG. 3, the abutments 25 and 26 are carried by a plate 28 adapted to pivot around a stationary pivot pin 29 registering with the middle point 12 of the balance 11, when the latter bears against its abutments 25 and 26. The oscillations of the plate 28 are controlled by a heart-shaped cam 31 engaged by two cam followers 32 carried by a lever 33 pivotally secured to the plate 28. Each revolution of the cam 31 produces two oscillations of the plate 28 in opposite directions, said oscillations having as a result to impart to the abutments 25 and 26 their oscillating movements. The shaft 34, to which the cam 31 is keyed executes one half a stroke for each revolution of the batten in a manner such that one of the two abutments 25 or 26 recedes for each stroke of the batten. The cam 31 is keyed to the shaft 34 in a manner such that the receding movement of the abutment 25 or 26 is performed exactly at the moment at which the edge of the blade 18 or 19 reaches the level of the nose 14a or 15a of the hook 14 or 15.

Each hook 14 or 15 engages through its tail piece a respective selecting lever 21 or 22. The selecting levers are pivotally secured to pins 35 and 36 on the plate 28 (FIG. 3) and the levers are normally urged against the surface of the corresponding abutments 25 or 26 by the springs 37 and 38. For the normal positions of the levers 21 and 22, that is when said levers engages the abutments 25 and 26, the hooks 14 and 15 are held in their retracted or inoperative position with reference to the paths of the edges of the blades 18 and 19.

When the plate 28 undergoes a rocking movement, it carries along with it not only the abutments 25 and 26, but also the selecting levers 21 and 22 associated therewith. For instance, when the abutment 25 occupies the position illustrated in dot-and-dash lines in FIG. 2, the lever 21 occupies also the position illustrated in dot-anddash lines in said FIG. 2, said position being that corresponding to selection.

When the reading system controls the selection through the lever 21, for instance, when the latter is in a selecting position, a bolt 39 is rocked into the position illustrated in dot-and-dash lines in FIG. 2 in a manner such that it holds the lever 21 in its selecting position by reason of said bolt engaging a notch 21a at the end of said lever. Once the selection is performed and while the blade 18 resumes forward travel, the hook 14 is released to operative position by the lever 21 which cannot follow the abutment 25 so that the spring 16 rocks the hook back in the direction of the arrow 41 and the nose 14a of said hook enters the path followed by the edge of the blade 18. At the end of the forward movement of the abutment 25, the blade 18 returns into engagement with the nose 14a of the hook 14 and carries it along, which causes a rocking of the balance 11 around the cam follower 24 into the position illustrated in dot-and-dash lines in FIG. 2 so as to shift the middle point 12 of said balance into the position illustrated at 12a. This shifting causes an actuation of the lever 10 and a raising of the heald frame 2 corresponding thereto. By reason of the simultaneous progression of the blade 18 and of the abutment 25, the hook 14 moves in parallelism with the blade 18 and enough time is left for it to enter the position defined by the weave design when required. This being performed with a release spacing reduced to a strict minimum. Furthermore, by reason of the blade 18 being accompanied by the hook 14, the drive of the latter by said blade is performed without any shock and the movement is all the smoother when the release is executed over a shorter spacing.

FIG. 4 shows an advantageous embodiment of the arrangement driving the blades 18 and 19. The latter are carried by T-shaped levers 42, said levers being pivotally secured at their middle points to a stationary shaft 43. These levers 42 undergo a reciprocating movement under the action of a connecting rod 44 carried by an eccentric member 45; said eccentric member 45 is keyed to the above-mentioned shaft 34 which carries also the cam 31.

The reading of the weave may be executed either mechanically or electrically,

A mechanical reading allows the dobby to operate with designs executed on boards of wood, nylon or metal provided with keys, whereas electric reading allows operating as desired either with wood, nylon or metal boards or with weaves drawn on perforated paper, metal or plastic material of any type.

In the case of a mechanical reading, as illustrated in FIG. 7, the weaves are executed by means of boards 47 made of nylon, wood or any other suitable material provided with keys 48 made of wood, plastic material, metal or the like conventional material and which may in fact be of a standard type used in present dobbies.

The cylinder 49 carries the small boards 47 controlled conventionally by the shaft controlling the dobby through the agency of a worm gear or of a modification incorporating pinions and a chain. Such arrangements are in fact conventional.

The keys 48 fitted on the boards 47 raise as they pass plates pivotally secured at axles 52. Said plates are of the type used in conventional dobbies. At their ends 51a is secured a cable 53 which serves for controlling the bolt 46 which holds the selecting levers 22 in position. The yielding cable 53 may be fitted in a sheath 53a and be associated with adjusting means 54 as illustrated in FIG. 7; it also may be guided in a bare condition by a system of pulleys. A return spring 55 urges the retaining bolt to a position which makes it engage the selecting lever 22. When a key 48 raises the plate 51, the latter releases the cable 53. The retaining bolt 46 urged by the spring 55 pivots and locks the selecting lever 22. As already mentioned, this leads to an engagement of the hook 15 by the blade 19 and the heald frame 2 is urged into its upper position. In contradistinction, when the board 47 does not carry a key 48, the plate 51 is urged back by the spring 56 into engagement with the stop 57 so that it rocks around its axle 52. Its end 51a exerts a tractional action on the cable 53 so that the retaining bolt 46 is caused to pivot in a reverse direction and release the selecting lever 22 thereby preventing hook 15 from being engaged by the blade 19. The heald frame 2 is then in its lower position; the reading is thus identical with that of conventional dobbies.

The electric reading may be executed by different means. One of these is illustrated in FIG. 8 and includes a conventional system of boards'47 and keys 48 cooperating with plates 51 pivoting around axles 52 and urged by springs 56 into positions identical with those obtained with a mechanical control. The rear end 51b of each plate 51 is in contact with the movable blade 58a of a switch 58. When the plate 51 does not contact'a key 48, its end 51b holds the switch blade 58a in a raised position, and consequently the switch 58 opens the circuit. In contradistinction, when the plate 51 is raised by a key, its end 51b lowers and allows the blade 58a of the switch 58 to engage the cooperating blade 58b so as to close the electric circuit.

Said electric circuit including a DC. supply 59 under a low voltage and an electro-magnet 61 acting directly on one of the arms of the'retainin'g bolt 46 so as to produce, when the circuit is closed, a pivotal movement of said bolt 46 in a direction such that it locks the selecting lever 22. Consequently, the reading is then identical with that of a mechanical control.

The blades 58a and 58b forming the switch 58 may be replaced by a mechanical or magnetic microswitch. In the case of a magnetic switch, the end 51b of the blade 51 carries a permanent magnet which produces the closing of the circuit by means of a suitable miniature switch.

If the dobby is used for a single direction of operation,

and is not necessary to make it revolve selectively forranged in staggered relationship. The use of such a paper and of this conventional reading system, requires a rotation of a cylinder and a two-pick reading.

The weave paper 62 is thus carried along by a conventional cylinder driven by a Worm gear in the same manner as in all standard dobbies. The paper slides over the metal plates 63 and 64 which extend each over one quarter of a cylinder and are insulated from each other. Above the plates 63 and 64, are arranged contact blades 65 and 66 in a manner such that the contact piece of the blade 65 lies above the slideway plate 63 while the contact piece on the blade 66 is located above the slideway plate 64. The contact blades 65 and 66 are raised by a mechanical member at the moment at which the cylinder driving the paper moves and the shifting of the paper is performed as in conventional dobbies, in other words between two selecting operations; the contact blades 65 and 66 are connected electrically through circuits illustrated in FIG. 11, which circuits lead to electromagnet 67 or 68 identical with the electromagnet 61 illustrated in FIG. 8. Each electro-magnet 67 or 68 plays the same part as that described with reference to the electromagnet 61.

The slideway plates 63 and 64 are connected electrically with a reversing switch 69 which ensures the closing of the electric circuit either through the plate 63 or through the plate 64 according as to whether the dobby operates in a forward or in a rearward direction. Thus, by a suitable switching of said plates, the order in which the rows are read may be shifted, which ensures a forced integral movement.

In all the reading arrangements described, that is both in the case of the mechanical and of the electrical arrangement, the connections are highly adaptable and consequently, it is possible to resort to conventional reading means such as the boards 47 or the paper designs 62 with a predetermined spacing, say 10 or 12 mm. which is a standard spacing, while the actual dobby is executed with a different subdivision, that is with different intervals between the axes of the hooks, balances and tractionally acting levers. It is, for instance, possible to read the design drawn on a paper subdivided by lines spaced by 12 mm. apart and to execute the dobby with a subdivision of 15 or 20 mm. The adaptability of the connecting means is in all cases sufficient to allow said difference in spacing.

In the case of a reading of a paper design 62 and by reason of the instantaneous control of the retaining bolts by the reading system, the dobby ensures an integral forced movement, which means that it can operate forwardly and rearwardly without any preliminary modification in the position of the cylinder. The arrangement of the bolts 39 and 46 and the part played by them, allows extending the time of reading sufficiently for ensuring a complete reliability for said reading.

What I claim is:

1. In a dobby provided with reading means, the pro vision of means adapted to control heald frames in a loom and comprising a balance, the middle point of which is operatively connected with a heald frame, abutments adapted to normally engage the ends of said balance, a hook pivotally secured to each end of the balance and movable between operative and inoperative positions under the control of the reading means, a blade associated with each hook and adapted to engage and shift the corresponding hook together with the balance away from the normal location of the cooperating abutment once for every two operative cycles of the loom, means for shifting in alternation each abutment away from and back towards the corresponding end of the balance simultaneously with the forward movement of the corresponding blade, and means whereby the rearwardmovement of each abutment produces a movement of the corresponding hook into operative position into the path of the cooperating blade, such movement of said hook in a direction to accompany the blade being prior to its engagement therewith.

2. A dobby as claimed in claim 1, wherein said means 7 for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot about its center which registers with the middle point of the balance when the latter is normally positioned and a lever controlling the angular position of said plate to shift the abutments alternatingly away from the balance.

3. A dobby as claimed in claim 1, wherein said means for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot around its center which registers with the middle point of the balance when the latter is normally positioned, a lever controlling the angular position of said plate to shift the abutments alternatingly away from the balance, said means for producing movement of the hooks comprising selecting levers pivotably connected to said plate for cooperating with respective abutments, springs urging the selecting levers into engagement with the respective abutments on the sides thereof facing away from the balance, bolts controlled by the reading means and adapted to hold said selecting levers away from the abutments, said selecting levers including bosses for acting on said hooks to normally hold the same in their inoperative positions out of the paths of the blades, further springs urging the hooks away from the lever bosses upon positioning of the selecting levers where they are held by the bolts to allow said hooks to move to operative position and enter the path of the corresponding blades.

4. A dobby as claimed in claim 1, wherein the means for shifting the abutments includes a shaft executing one half revolution of each complete cycle of the loom, a heart-shaped cam keyed to said shaft and controlling the movements of the abutments, an eccentric member carried by said shaft and a T-shaped lever carrying the blades and coupled to said eccentric member for undergoing oscillatory motion which controls the movement of said blades with reference to the hooks.

5. A dobby as claimed in claim 1, wherein said means for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot around its center which registers with the middle point of the balance when the latter is normally positioned, a level controlling the angular position of said plate to shift the abutments alternatingly away from the balance, said means for producing movement of the hooks comprising two selecting levers secured to said plate and provided with bosses normally holding the hooks in inoperative position out of the path of the blades, springs urging said selecting levers into engagement with the abutments on the sides thereof facing away from the balance, bolts adapted to hold said levers away from the abutments, further springs urging the hooks away from the levers bosses upon positioning of the selecting levers where they are held by the bolts to allow said hooks to enter the corresponding blade path and an adaptable connection between the reading means and the bolts.

6. A dobby as claimed in claim 1, wherein said means for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot about its center which registers with the middle point of the balance when the latter is normally positioned, a lever controlling the angular position of said plate to shift the abutments alternatingly away from the balance, said means for producing movement of the hooks comprising two selecting levers pivotally secured to said plate and provided with bosses normally holding the hooks in inoperative position out of the path of the blades, springs urging said selecting levers into engagement with the abutments on the sides thereof facing away from the balance, bolts adapted to hold said selecting levers away from the abutments, further springs urging the hooks away from the lever bosses upon positioning of the selecting levers where they are held by the bolts to allow said hooks to enter the corresponding blade path, elastic means normally holding said bolts in their lever engaging position and cables connecting the reading means with the bolts to release same against the action of said elastic means.

7. A dobby as claimed in claim 1, wherein said means for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot around its center which registers with the middle point of the balance when the latter is normally positioned, a lever controlling the angular position of said plate to shift the abutments alternatingly away from the balance, said means for producing movement of the hooks comprising two selecting levers pivotally secured to said plate and provided with bosses normally holding the hooks in inoperative position out of the path of the blades, springs urging said selecting levers into engagement with the abutments on the sides thereof facing away from the balance, bolts controlled by the reading means and adapted to hold said selecting levers away from the abutments, further springs urging the hooks away from the lever bosses uopn positioning of the selecting levers where they are held by the bolts to allow said hooks to enter the corresponding blade path, elastic means normally holding said bolts in their lever engaging position, an electromagnet controlling the operation of each bolt to release same against the action of said elastic means, a circuit feeding said electromagnet, and a switch controlling opening and closing of said circuit.

8. A dobby as claimed in claim 1, wherein said means for shifting the abutments in alternation comprises a plate carrying at its ends the two abutments and adapted to pivot around its center which registers with the middle point of the balance when the latter is normally positioned, a lever controlling the angular position of said plate to shift the abutments alternatingly away from the balance, said means for producing movement of the hooks comprising two selecting levers pivotally secured to said plate and provided with bosses normally holding the hooks in inoperative position out of the path of the blades, springs urging said selecting levers into engagement with the abutments on the sides thereof facing away from the balance, bolts controlled by the reading means and adapted to hold said selecting levers away from the abutments, further springs urging the hooks away from the lever bosses upon positioning of the selecting levers where they are held by the bolts to allow said hooks to enter the corresponding blade path, elastic means normally holding said bolts in their lever engaging position, an electromagnet controlling the operation of each bolt to release same against the action of said elastic means, a circuit feeding said electromagnet, a switch controlling opening and closing of said circuit and a pivoting member controlled by the reading means and controlling said switch.

9. A dobby as claimed in claim 1, wherein said reading means includes two part cylindrical metal supports together forming half a cylinder and over which a perforated strip is adapted to move, and a row of contact pieces cooperating with each support, a circuit passing through each contact piece and means whereby the closing of the circuit through the registering of a perforation with the contact piece in said circuit acts on a cooperating balance hook.

References Cited UNITED STATES PATENTS 2,438,796 3/1948 Zollikofer 13972 2,712,327 7/1955 Davies et a1. 13971 3,192,957 7/1965 ONeill 13957 XR 3,285,291 11/1966 Flavre 139-68 3,307,591 3/1967 Staubli 139-71 FOREIGN PATENTS 959,899 4/ 1957 Germany. 253,240 11/ 1948 Switzerland.

HENRY S. JAUDON, Primary Examiner. 

